I actually just read that the PS passed the XBox is worldwide console sales this christmas season. It had been propped up by the Japanese market, but they've had a few boosts with the redesign slims a couple times, and have of late done a lot better on the software front than MS.

The big mistake, even moreso than the price, was coming late to the market.

And as for the notion that PS4 won't play used games, there's almost no way they'd do this unless MS did it too. And frankly if both systems don't do it, it's very possible the game manufacturers take this into their own hands. It was talked about extensively with Arkham City. By getting the game itself to only reveal some critical element with only a purchased code, which in the case of Batman was going to be the cape. So if you bought the game used you'd have to get your hands on the code for the cape, which would be SN exclusive, and they'd be able to tell if it was used or not.

I'm obviously not a fan of the idea, but I certainly understand it from the gaming company's perspective, and frankly I almost never buy used games. It's not Sony or Microsoft who suffers from the secondary market, it's the developers.
Maybe Sony could use the software to convince developers to work more exclusively with them if they can block that market and XBox can't.